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APPROXIMATION ALGORITHM FOR MAX-BISECTION PROBLEM WITH THE POSITIVE SEMIDEFINITE RELAXATION

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Journal of Computational mathematics 2003年第3期21卷 357-366页

作者： Da-chuan Xu Ji-ye Han(institute of applied {2., academy of {2. and System sciences, chinese academyof sciences, beijing 100080, China) institute of Applied Mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences 北京 100080

Using outward rotations, we obtain an approximation algorithm for Max-Bisection problem, i.e., partitioning the vertices of an undirected graph into two blocks of equal cardinality so as to maximize the weights of crossing edges. In many interesting cases, the algorithm performs better than the algorithms of Ye and of Halperin and Zwick. The main tool used to obtain this result is semidefinite programming.

关键词： Approximation algorithm Max-Bisection problem Semidefinite programming Approximation ratio.

Global Convergence of the Broyden's Class of Quasi-Newton Methods with Nonmonotone Linesearch

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Acta Mathematicae Applicatae Sinica 2003年第1期19卷 19-24页

作者： Da-chuan Xuinstitute of applied {2., academy of {2. and System sciences, chinese academy of sciences, beijing 100080, China institute of applied {2. Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China

Abstract In this paper, the Broyden class of quasi-Newton methods for unconstrained optimization is investigated. Non-monotone linesearch procedure is introduced, which is combined with the Broyden's class. Under the ... 详细信息

关键词： Keywords Quasi-Newton method Broyden class non-monotone linesearch global convergence unconstrained optimization

Integrated precise orbit determination of Shenzhou IV unmanned spacecraft

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Science China(Technological sciences) 2004年第5期47卷 518-525页

作者： L Congmin1,2. GU Yidong3, LIN Baojun3 & GUO Jiong3 1. Center for Space Science and applied Research, chinese academy of sciences,{2., China 2. Graduate School of the chinese academy of sciences, beijing 100039, China 3. General Establishment of Space Science and Application, chinese academy of sciences,{2., China Correspondence should be addressed to L Congmin 1. Center for Space Science and applied Research Chinese Academy of Sciences 100080 Beijing China 2. Graduate School of the chinese academy of sciences 100039 Beijing China 3. General Establishment of Space Science and Application Chinese Academy of Sciences 100080 Beijing China

Considering the characteristic orbit of Shenzhou IV spacecraft and the advantages and disadvantages of several types of domestic orbit measurements, a scheme of IPOD is determined, which uses GPS, SLR and USB observation data jointly plus precise ionosphere corrections to GPS observation data. IPOD system and mathematic models of OD are introduced. The results of different joint OD are analyzed using true observation data, and show that radial accuracy is better than 2.m.

关键词： Shenzhou IV unmanned spacecraft integrated precise orbit determination GPS SLR USB.

A note on n-edge chromatic number

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chinese Science Bulletin 1997年第23期42卷 1952-1954页

作者： SUN Liang and ZHANG Zhongfu1. Department of applied mathematics, {2. institute of Technology, {2. 100081, China 2. institute of applied mathematics, Lanzhou institute of Railway, Lanzhou 730070, China Department of applied mathematics Beijing Institute of Technology Beijing 100081 China

ALL graphs appearing in this note are simple. A graph with p vertices and q edges will becalled a (p, q )-graph. The maximum degree of G is denoted by Δ(G).Let n≥2.be an integer. The n-edge chromatic number X_n (G) of a simple graph G is theminimum cardinality of a set of colors with which one can assign the colors to the edges of Gsuch that the edges on a path of length less than or equal to n receive different *** aim of this note is to explore the bounds for X’_n (G) and X’_n (G) + X’_n (G). It is

关键词： graph complement n-edge chromatic number.

The asymptotic stability of multistep multiderivative methods for systems of delay differential equations

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Communications in Nonlinear Science and Numerical Simulation 2000年第1期5卷 24-26页

作者： Chengming HUANG and Qianshun CHANG institute of applied mathematics, chinese academy of sciences, P. O. Box 2.34,{2., China institute of applied {2. Chinese Academy of Sciences P. O. Box 2734 Beijing 100080 China

This paper deals with the asymptotic stability of multistep multiderivative methods for systems of delay differential equations. In particular, it is shown that A-stability of multistep multiderivative methods for ord... 详细信息

关键词： delay differential equation stability multistep multiderivative methods

Numerical study on scanning radiation acoustic field in formations generated from a borehole

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Science China(Physics,Mechanics & Astronomy) 2005年第2期48卷 247-256页

作者： CHE Xiaohua1, ZHANG Hailan1, QIAO Wenxiao2.& JU Xiaodong2.1. institute of Acoustics, chinese academy of sciences,{2., China 2. Faculty of Natural Resources & Information Technology, University of Petroleum, beijing 102.49, China institute of Acoustics Chinese Academy of Sciences Beijing 100080 China Faculty of Natural Resources & Information Technology University of Petroleum Beijing 102249 China

Numerical study on scanning radiation acoustic field in formations generated by linear phased array transmitters in a fluid-filled borehole is carried out using a real axis integration (RAI) method. The main lobe width of the acoustic beams and the incident angle on the borehole wall can be controlled by means of adjusting parameters, such as the element number and the delay time between the neighboring array elements of linear phased array transmitter. The steered angle of longitudinal waves generated in the formation satisfies the Snell’s law for plane waves when the incident angle on the borehole wall is less than the first critical angle. When the lobe width of the acoustic beams is narrow and the steered angle is less than the first critical angle, the acoustic field in the formation can be approximately calculated given that the linear phased array is put in the formation without borehole. The technique of scanning radiation acoustic field can be applied to enhancing investigation resolution and signal-to-noise ratio in crosswell seismic survey and borehole acoustic reflection imaging.

关键词： formation, linear phased array transmitter, steered angle, RAI, scanning radiation.

High Throughput SNP Genotyping with Two Mini-sequencing Assays

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Acta Biochimica et Biophysica Sinica 2004年第6期36卷 379-384页

作者： Chunqing LUO1,2., Libin DENG1#, and Changqing ZENG1,2. The institute of Genetic and Developmental Biology, the chinese academy of sciences, {2. 100101, China 2.2. Genomics institute, the chinese academy of sciences, {2. 101300, China The institute of Genetic and Developmental Biology the Chinese Academy of SciencesBeijing 100101 China beijing Genomics institute the Chinese Academy of SciencesBeijing 101300 China

Two mini-sequencing methods, FP-TDI (template-directed dye-terminator incorporation with fluorescence-polarization) and MassArray (matrix assisted laser desorption ionization time of flight detection mass spectrometry), were optimized. A numeric standard was introduced to evaluate the SNP scoring quality of FP-TDI assay, thus made the optimization work easier. At the same time, using multi-PCR technology, 8-plex genotyping of MassArray assay was successfully carried out, some softwares were developed and the data process of MassArray was highly automated. Then these two methods were applied to high throughput SNP genotyping, the accuracy, efficiency and robustness were compared. The result shows FP-TDI is more sensitive to the concentration of SNPprimer and PCR product, as well as extension cycles, the SNPprimer length of FP-TDI should be 2.–30 bp long, whereas MassArray assay prefers to be as short as only 16 *** 6440 SNP sites of human chromosome 3 were genotyped in a sample of 90 individuals, 4792.sites by FP-TDI assay and 1648 sites by MassArray assay, the success rates of FP-TDI and MassArray were 67.7% and 93.6% respectively. The throughput of MassArray was higher than FP-TDI, and the cost of MassArray was lower, MassArray was more suitable for high throughput SNP genotyping.

关键词： SNP genotyping FP-TDI MassArray high throughput

Transient species and its properties of melatonin

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Science China Chemistry 2006年第4期49卷 308-314页

作者： ZHU Hongping1,2. ZHANG Zhaoxia1,2. ZHAO Hongwei1, WANG Wenfeng1 & YAO Side1 1. Shanghai institute of applied Physics,{2., Shanghai 2.1800, China 2. Graduate University of the{2., beijing 100049, China 1. Shanghai institute of applied Physics Chinese Academy of Sciences Shanghai 201800 China 2. Graduate University of the chinese academy of sciences Beijing 100049 China

The photo-physical and photo-chemical properties of melatonin (ML) werestudied by 2.6 nm laser flash photolysis (LFP). ML undergoes photo-ionization to produce radicalcation of ML (ML^(·+))and hydrated electrons (e_(aq)^-), while excited triplet state ~3ML~* is alsoformed during photolysis. The oxidation via one electron transfer from ML to SO_4^(·+) and thetriplet state of riboflavin (~3RF~*) has been also investigated and the rate constants for theprocess have been determined to be 8.0x10^9 and 1.4x10^9 L·mol^(-1)·s^(-1) respectively. Theradical cation of 2.2.'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS^(·+)) scavengingcapacities of melatonin and other antioxidants are compared in this paper.

关键词： melatonin, laser flash photolysis, photoionization, triplet state.

Time-variation of the near 5-month period of sunspot numbers

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chinese Science Bulletin 2002年第23期47卷 1969-1973页

作者： HAN Yanben1 & HAN Yonggang1,2.. National Astronomical Observatories, chinese academy of sciences, beijing 100012. China 2. Department of {2. mathematics, beijing Polytechnic University, beijing 10002., China National Astronomical Observatories Chinese Academy of Sciences Beijing China Department of applied mathematics Beijing Polytechnic University Beijing China

The variation of the near 5-month period of sunspot numbers is discussed on the basis of the wavelet transform of the daily sunspot number series in the 14th-2.nd solar cycles. The result shows that the period exists in every cycle and its energy density (amplitude) is comparatively large in the peak section of the cycle. In the distinct cycle, the length and intensity of the period is different, which means that the period varies with time. The near 2.-day period is also analyzed and it is found to be time-variable and even not very stable in the peak section of the cycle. The variations of the two periods show that the near 5-month period should not be simply regarded as the multiples of the near 2.-day period.

关键词： solar activity sunspot time-variation wavelet.